Ketosis

• Definition:
  Ketosis is a metabolic condition characterized by elevated ketone bodies - acetoacetate, β-hydroxybutyrate, and acetone - in blood (>1 mmol/L; normal: <0.2 mmol/L) due to increased fat breakdown and incomplete oxidation in carbohydrate deficiency.

• Causes:

  • Prolonged fasting / starvation

  • Uncontrolled diabetes mellitus (especially Type 1)

  • Low-carbohydrate, high-fat diets

  • Prolonged exercise

• Biochemical Basis:

  • Occurs when acetyl-CoA from β-oxidation exceeds the capacity of the TCA cycle (due to low oxaloacetate).

  • Excess acetyl-CoA is converted into ketone bodies in the liver mitochondria.